Fluid-operated acoustic device



March 1, 1966 B. M. HORTON FLUID-OPERATED ACOUSTIC DEVICE 6 Sheets-Sheet1 Original Filed Sept. 19, 1960 i INVENTOR BILL Y M. HORTON bug 'rokAIEY March 1, 1966 B. M. HORTON 3,237,712

FLUID-OPERATED ACOUSTIC DEVICE Original Filed Sept. 19, 1960 6Sheets-Sheet 2 INVENTOR BIL L Y M HORTON BY a. J. W

ATTORNEY March 1, 1966 B. M. HORTON 3,237,712

FLUID-OPERATED ACOUSTIC DEVICE Original Filed Sept. 19, 1960 6Sheets-Sheet 5 AMPLIFIED VOICE OUT AMPLIFIED VOICE OUT VOICE IN INVENTORBILLY M. HORTON BY QIJW ATTBRNEY March 1, 1966 HORTQN 3,237,712

FLUID-OPERATED ACOUSTIC DEVICE Original Filed Sept. 19, 1960 6Sheets-Sheet 4 FIG. 8

INVENT OR BILLY M. HORTON BY 6L0. 09 4M March 1, 1966 B. M. HORTON3,237,712

FLUID-OPERATED ACOUSTIC DEVICE Original Filed Sept. 19, 1960 6Sheets-Sheet 5 IIIIIIIIIiII/IIIIIIIIII INVENTOR B/LLY M. HORTON BY Q.Q]. W

ATTaRn/EY March 1, 1966 HORTON 3,237,712

FLUID-OPERATED ACOUSTIC DEVICE Original Filed Sept. 19, 1960 6Sheets-Sheet 6 BILL) M. HORTON BY 62.3- W

ATTORNEY United States Patent Ofi ice 3,237,712 Patented Mar. 1, 19663,237,712 FLUID-OPERATED ACOUSTIC DEVICE Billy M. Horton, Rock CreekHills, Md. (9712 Kensington Parkway, Kensington, Md.) Originalapplication Sept. 19, 1960, Ser. No. 51,896, now Patent No. 3,122,165,dated Feb. 25, 1964. Divided and this application Nov. 20, 1962, Ser.No. 258,363 12 Qlaims. (Cl. 181-.5) (Granted under Title 35, US. Code(1952), sec. 266) This application is a divisional application of mycopending application Serial No. 51,896, filed September 19, 1960, nowPatent No. 3,122,165, for Fluid-Operated System. Serial No. 51,896 is acontinuation-in-part of my application No. 848,878, filed October 26,1959, now abandoned, for Fluid Amplifier System.

The invention described herein may be manufactured and used by or forthe Government for governmental purpose without the payment to me of anyroyalty thereon.

This invention relates to a fluid-operated system which utilizes theflow of a fluid so that the system performs functions which areanalogous to functions now being performed by electronic components andsystems.

Electronic systems and components are capable of performing suchfunctions as detecting and amplifying a signal. However, it is alsodesirable that systems other than electronic perform the same oranalogous functions without requiring a source of electrical energy ordelicate electronic components. While known mechanical systems willperform functions analogous to functions performed by electronicsystems, these systems require large numbers of moving parts. Failure inany part usually results in improper operation or failure of the system.

Broadly, therefore, it is an object of this invention to provide afluid-operated system which performs functions analogous to functionsperformed by existing electronic systems such as fluid operated acousticdevice in this disclosure.

More specifically, it is an object of this invention to utilize the flowof a stream of fluid under pressure so that the fluid acts in a mannersimilar to the manner in which electrons act in electronic systems.

It is a further object of this invention to provide a fluidoperatedsystem in accordance with the above objects which requires no movingparts.

According to this invention the energy of a fluid stream is utilized ina unique system which has no moving parts. The system utilizes apressurized fluid stream in a manner such that the fluid performssimilar functions to those performed by electrons in existing electronicsystems. Using the principles of this invention such functions asmultiplication and amplification can be performed.

More specifically, the present invention relates to fluid amplifiersemploying no moving parts in which amplification depends upon magnitudeor deflection of a stream of fluid resulting from controlled fluidpressure gradient provided transversely of the direction of flow of thefluid stream.

In fluid amplifiers of the type with which the present invention isconcerned, a fluid stream, hereinafter referred to as the power stream,issues from a nozzle or orifice constructed such that the power streamis well defined in space. In a specific example of one type of fluidamplifier, a control fluid stream is directed toward the power stream ina direction generally perpendicular thereto, to provide a differentialpressure or pressure gradient across the power stream. The apparatus isprovided with at least two outlet or fluid recovery apertures orpassages, facing the power stream, and the recovery apertures orpassages are arranged such that when the power stream is undeflected bythe control stream, all of the fluid of the power stream is directed toa first of the outlet passages. The first outlet passage is returned toa sump, and a load device is associated with a second of the outletpassages.

The control stream being directed generally transversely of the powerstream, an interaction occurs between the two streams, resulting indeflection of the power stream to an extent, that is, through an angle,which is related to the energy and momentum of the control stream.Deflection of the power stream results in delivery of a portion of thepower stream to the second outlet passage where some of the kineticenergy of the power stream entering the second outlet passage may berecovered, or where the fluid so directed may be delivered to autilization device. It has been found that a low energy control streamcan deflect a well-defined, high energy power stream to the extentrequired to cause a substantial portion of the power stream to bedelivered to the second output passage, and that the integrity, i.e.,the well defined character, of the power stream is retained suflicientiyafter interaction of the two streams that the total energy or change intotal energy delivered to the second outlet passage can be greater thanthe energy or change in energy required to accomplish this deflection.Thus, since the changes in energy at the load device produced bydeflection of the stream are greater than the changes in energy requiredto produce the deflection, the apparatus is capable of amplification,and can produce a power gain. The gain achievable with a particularsystem is, to a degree, dependent upon the spacing between the outletpassages and the nozzle, hereinafter called the power nozzle, from whichthe power stream issues. If the outlet passages are located close to thepower nozzle then relatively large angular deflections of the powerstream are required to produce any substantial change in thedifferential quantity of fluid delivered to the outlet passageapertures. More specifically, the change in relative energies deliveredto the outlet passages is a function of the angle through which thepower stream is deflected. If the outlet passages are considered to belocated on an arc of a circle, the deflection is equal to the angle ofdeflection in radians times the radius of the circle. This radius isequal to the distance between the point of interaction of the twostreams and the outlet apertures or passages. Ideally, therefore, theoutlet apertures or passages should be spaced as far as possible fromthe point of interaction of the two streams, so as to minimize the anglethrough which it is required to deflect the power stream in order toproduce a predetermined change in energy at the outlet passages.However, the distance that the outlet passages may be located from thepoint of interaction of the two streams is limited by the amount ofspread and loss of integrity of the power stream as a function ofdistance. When two gas jets interact in a gaseous atmosphere, the powerstream begins to lose its integrity at a relatively short distance fromthe point of interaction of the streams, and this causes a loss ofkinetic energy which limits the power gain of the amplifier.

In accordance with another feature of the present invention, theinteracting streams can be confined in a plane parallel to the plane ofdeflection of the power stream, hereinafter called the deflection plane.It has been found that by preventing expansion of the fluid stream in adirection perpendicular to, or normal to the deflection plane,hereinafter called the N direction, the distance over which the powerstream retains its integrity is greatly increased. In consequence, theoutlet passages may be placed at a considerable distance from the pointof interaction of the streams and therefore the angle through which thepower stream must be deflected to achieve a predetermined change inpower at one of the output passages is greatly decreased; and the gainof the system is proportionately increased. Specifically, it has beenfound that by confining the stream to the deflection plane, i.e., bypreventing spreading in the N direction, the outlet apertures orpassages may be displaced distances from the nozzle which are muchgreater than the width of the power nozzle without serious loss ofintegrity of the power stream and without a serious loss of energy dueto degradation or spreading of the power stream.

Another feature of the invention is to employ a V- shaped dividerbetween the two outlet passages, so that the apex of the V presentssubstantially a line division between the two outlet passages. Therebythe amount of deflection required to switch energy from one passage toanother is minimized. Further by appropriately shaping the divider,and/or choosing the angles of the side walls of the divider, it producesa minimum of interference with the flow patterns established in theapparatus. Also if the power stream is normally directed in itsundeflected position directly toward the apex of the divider, so thatthe mass flow divides equally between the two output passages, gain canbe further enhanced. In such an apparatus, the load device may beconnected across the two outlet passages so as to respond to thedifferential output from the passages. When the power stream isdeflected, the power applied to one outlet passage is subtracted fromthe power supplied to the other outlet passage, and therefore has atwo-fold or push pull effect upon the energy delivered to the loaddevice. Employing all of the techniques described above, single stagegains of greater than 60 are in some cases achievable.

It has been stated hereinabove that the efficiency of the presentinvention depends upon maintaining the integrity of the power streamthrough sufficiently large angles of deflection that the power deliveredto a load device on deflection of the power stream is greater than thepower required to produce this deflection.

Loss of integrity of the stream, in a properly designed unit isprimarily a spreading and slowing of the stream, and in order tounderstand the effects of stream spreading on the gain of the system,two factors must be considered. One factor to be considered is the typeof gain which the apparatus is attempting to achieve and the secondfactor is the type of stream or jet employed.

There are two well-recognized types of jet systems, i.e., the free jetand the submerged jet. In the case of a submerged jet, such as an airjet in an air atmosphere, the viscous drag of the surrounding medium onthe submerged stream has an appreciable effect upon the stream whichslows down the sides of the stream and produces a nonuniform totalpressure there across. Maximum pressure of the stream is usually foundin a relatively narrow region along its longitudinal axis, and inconsequence, if it is desired to produce a pressure amplifier, theoutlet apertures or passages are constructed to sense a narrow region atthe center of the stream so that small deflection angles produce largechanges in the pressure of the portions of the power stream impinging oneach aperture. A second type of amplification is mass flowamplification, wherein the outlet passages of an amplifier areconstructed to accumulate all of the fluid in the power stream, orentrained with the power stream. A third type of amplifier is a poweramplifier and this unit employs an outlet passage intermediate in sizebetween the passages employed in the two prior cases. The size of theoutlet passages for the power amplifier is such that the product ofpressure and volume flow is maximized. The load device with which anamplifier is to be employed takes various forms, which normallydetermines the type of amplification employed. A mechanical load forperforming work usually requires a power amplifier. If the output fluidof a unit is to be employed to drive a second diaphragm-actuated valveor a fluid amplifier stage in cascade, then pressure amplification maybe required. Mass flow amplification is employed where a great volume offlow is desired and a small pressure can be tolerated.

The spreading of a submerged stream or jet in a fluid amplifier isaccompanied by reduction in the available output energy in the stream.With respect to pressure amplification, spreading of the stream isaccompanied by a loss of pressure along the sides of the stream due toentrainment of ambient fluid which is initially substantially at rest,thereby reducing the average pressure across the stream. In a mass flowunit, since one is merely collecting all of the fluid in the stream,spreading of the stream does not affect the quantity of fluid collectedbut spreading of the stream does in some cases produce contamination ofthe fluid stream. Therefore, in the submerged jet unit, it is importantto prevent spreading to whatever extent possible. Obviously spreading ofthe power stream in the direction of deflection cannot be entirelyprevented since room must be allowed for deflection of the power streambut, as indicated above, prevention of spreading in the N direction,which is perpendicular to or normal to the deflection plane, is possibleand results in a considerable increase in efficiency and achievable gainin a given unit over that achievable in a unit which does not preventspreading in the N direction.

The aforesaid factors, which are of great importance in a submerged jetunit, do not have a great effect upon the operation of a free jetsystem. In a perfect free jet system the effects of viscous drag of theambient fluid are negligible and the pressure profile of the free jet isuniform. However, a perfect free jet is not obtainable in practice andthe pressure across the jet is accordingly not absolutely uniform.

Prevention of spreading of the power stream in the N direction, i.e.,spreading in a direction normal to the deflection plane can beaccomplished by providing top and bottom walls extending parallel to thedirection of deflection, and appropriately spaced to permit use of apower stream of the desired size. These walls, however, introduceviscous losses into the system since the fluid adjacent to the wall isat rest and the power jet must provide the energy lost through increasedshearing and possibly turbulence between the moving and stationaryfluid. Consequently, limitations exist on depths of the unit in the Ndirection, and more specifically the quantity of the flowing fluidaffected by the walls must be small compared to the total flowing fluidin the power stream. In order to minimize this ratio, that is, to makethe quantity of fluid affected by the confining top and bottom wallssmall compared with the total fluid in the stream, the amplifier may bemade thick in the N direction compared with the width of the powernozzle.

A limiting factor on the thickness of the unit in the N direction is thefact that if the unit is made too thick the input signal employed tomodulate or alter the power stream may have different affects upondifferent portions of the power stream. If the various portions of thestream do not control the fluid in the power stream in time coincidence,then the ability of the amplifier to respond to rapidly changing controlsignals is impaired. This effect becomes serious when the amplifier ismade thick in the N direction.

This difiiculty can be largely overcome by a type of geometry, based oncircular symmetry, which has the advantage that top and bottom platelosses are eliminated. Specifically such a design is a toroidalconfiguration in which the power nozzle is a complete circle surroundedby toroidally-shaped outlet passages. Specifically, the toroidal unit isa figure of revolution of the planar type of amplifier taken about anaxis lying in the deflection plane. In a system of this type, the topand bottom walls no longer exist since the device closes upon itself.Spreading of the jet in the N direction in a unit of this type issubstantially prevented by the fact that each incremental portion of thepower stream is adjacent to fluid on both sides flowing in substantiallythe same direction. This arrangement provides a unit having lossestheoretically corresponding to an infinite displacement between top andbottom plates while retaining the benefits resulting from confining thejet. An apparatus of this type also eliminates the undesired effects,appearing in a planar unit having a large dimension in the N direction,which arise from the fact that the input control signal may arrive atdifferent times at different locations along the pow er stream. In atoroidal system, the control fluid may be fed to the control nozzlethrough a manifold which has substantially equal fluid path lengths fromthe input passage to all portions of the power stream.

A typical single stage amplifier, whether of the toroidal or planartype, or of-a type having other configurations, may comprise a powernozzle extending through an end wall of a chamber defined by the endwall and two outwardly diverging side walls, hereinafter referred to asthe left and right walls. A V-shaped or aerodynamically streamlineddivider is disposed at a predetermined distance from the end wall, theapex of the divider being located along the center line of the nozzlewith its sides generally parallel to the left and right side walls ofthe chamber. The regions between the divider and the left and right sidewalls define left and right outlet passages respectively. One or moreleft control nozzles extending through the left wall, or one or moreright control nozzles, or a combination of right and left controlnozzles are provided, each control nozzle being directed transversely tothe power nozzle.

In operation, fluid under pressure is supplied to the power nozzle and awell defined fluid stream, the power stream issues into the chamber.Control signals in the form of changes in pressure or flow rate aredeveloped at the control nozzles and the control streams issuing from orflowing into these nozzles produce deflection of the power stream in onedirection or the other depending upon Whether the signal is in the formof increased or decreased pressures, or flow rates, respectively. Theamplifier described immediately above is capable of performance as anyof several broad classes of fluid amplifier units. Two of these classesare:

(I) Those in which there are two or more streams which interact in sucha way that one or more of these streams deflect another stream withlittle or no interaction between the side walls of the chamber in whichthe streams interact, and the streams themselves. In such an amplifieror computer fluid element, the detailed contours of the side walls ofthe chamber in which the streams interact is of secondary importance tothe interacting forces between the streams themselves. Although the sidewalls can be used to contain fluid in the interacting chamber, and thusmake it possible to have the streams interact in a region at somedesired pressure, the side walls are placed in such a position that theyare somewhat remote from the high velocity portions of the interactingstreams. Under these conditions the flow pattern within the interactingchamber depends primarily upon the size, speed and the direction of thestreams and upon the density, viscosity, compressibility and otherproperties of the fluids in the streams. In the case of interacting freejets, i.e., those in which streams of fluid impinge upon one anotherwith no interaction between the streams and the side walls, and with noforces from fluids around the streams, momentum must be conserved. Thiscondition of momentum conservation can be approximated by interactingstreams of water in air, since the viscosity of air is much lower thanthe viscosity of water, and since water is much more dense than air. Aneven better approximation to the condition of momentum conservation byinteracting free jets is provided by the case of interacting jets ofliquid mercury in vacuum.

(11) The second broad class of fluid amplifier and computer elementscomprises those amplifier or computer elements in which two or morestreams interact in such a way that the resulting flow patterns andpressure distribution within the chamber are greatly affected by thedetails of the design of the chamber walls. The effect of side Wallconfiguration on the flow patterns and pressure distribution which canbe achieved with single or multiple streams depends on: the relationbetween width of the power nozzle and of the interacting chamber nearthe power nozzle; the angle that the side walls make with respect to thecenter line of the power stream; the length of the side wall (when adivider is not used); the spacing between the power nozzle and the flowdivider (if used); and the density, viscosity, compressibility anduniformity of the fluid. It also depends to some extent on the thicknessof the amplifying or computing element. Amplifying and computing devicesutilizing boundary layer effects, i.e., effects which depend upondetails of side walls configuration can be further subdivided into threecategories:

(a) Boundary layer elements in which there is no appreciable lock oneffect. Such a unit has a power gain which can be increased by boundarylayer effects, but these effects are not dominant;

(b) Boundary layer units in which lock on effects are dominant and aresuflicient to maintain the power stream in a particular flow patternthru the action of the pressure distribution arising from boundary layereffects, and requiring no additional streams other than the power streamto maintain that flow pattern, but having a flow pattern which can bechanged to a new stable flow pattern either by the supplying or removalof fluid thru one or more of the control nozzles, or by altering thepressures at one or more of the output apertures;

(c) Boundary layer units in which the flow pattern can be maintainedthru the action of the power stream alone without the use of any otherstream, which flow pattern can be modified by the supplying or removalof fluid thru the control nozzles, but which units maintain certainparts of the power stream flow pattern, including lock on to the sidewall, even though the pressure distribution at the output apertures ismodified.

In order to understand more fully the reasons for the lock-on phenomena,attention is called to the copending patent applications of Bowles andWarren, Serial Nos. 855,478 and 4,830, filed November 25, 1959, andJanuary 26, 1960, respectively, and both now abandoned (their subjectmatter having been incorporated in copending continuation-in-partapplication Serial No. 58,188, filed October 19, 1960), portions of thediscussions of which are reproduced herewith for the purposes of clarityof the present discussion only. The lock-on phenomena is due to aboundary layer effect existing between the stream and a side wall.Assume initially that the fluid stream is issuing from the main nozzleand is directed toward the apex of the divider. The fluid issuing fromthe orifice, in passing through the chamber, entrains fluid in thechamber and remove this fluid therefrom. If the fluid stream is slightlycloser to, for instance, the left wall than the right wall, it is moreeffective in removing the fluid in the region between the stream and theleft wall than it is in removing fluid between the stream and the rightwall since the former region is smaller. Therefore the pressure in theleft region between the left wall and stream is lower than the pressurein the right region of the chamber and a differential pressure is set upacross the jet tending to deflect it towards the left wall. As thestream is deflected further toward the left wall, it becomes even moreefiicient in extraining air in the left region and the pressure in thisregion is further reduced. This action is self-reinforcing and resultsin the fluid stream becoming deflected toward the left wall and enteringthe left outlet passage. The stream intersects the left wall at apredetermined distance downstream from the outlet of the main orifice;this point being normally referred to as the point of attachment. Thisphenomena is referred to as boundary layer lock-on. The operation ofthis type of apparatus may be completely symmetrical in that if thestream had initially been slightly deflected toward the right wallrather than the left wall, boundary layer lock-on would have occurredagainst the right wall.

Continuing the discussion of the three categories of the second class offluid amplifying elements, the boundary layer unit type a above utilizesa combination of boundary layer effects and momentum interaction betweenstreams in order to achieve a power gain which is enhanced by theboundary layer effects, but since boundary layer effects in type a arenot dominant, the power stream does not of itself remain locked to theside wall. The power stream remains diverted from its initial directiononly if there is a continuing flow out of, or into, one or more of thecontrol nozzles. Boundary layer unit type b has a sufiicient lock oneffect that the power stream continues to flow entirely out one aperturein the absence of any inflow or outflow signal from the control nozzles.A boundary layer unit type b can be made as a bistable, tristable, ormultistable unit, but it can be dislodged from one of its stable statesby fluid flowing out of or into a control nozzle or by blocking theoutput passage connected to the aperture receiving the major portion ofthe power stream. Boundary layer units type have a very strong tendencyto maintain the direction of flow of the power stream through theinteracting chamber, this tendency being so strong that completeblockage of the passage connected to one of the output apertures towardwhich the power stream is directed does not dislodge the power streamfrom its locked on condition. Boundary layer units type c are thereforememory units which are virtually insensitive to positive loadingconditions at their output passages.

To give a specific example: boundary layer effects have been found toinfluence the performance of a fluid amplifier element if it is made asfollows: the width of the interacting chamber at the point where thepower nozzle issues its stream is two to three times the width, W, ofthe power nozzle, i.e., the chamber width at this point is 3W; and theside walls of the chamber diverge so that each side wall makes a 12angle with the center line of the power stream. In a unit made in thisway, a spacing between the power nozzle and the center divider equal totwo power nozzle widths 2W will exhibit increased gain because ofboundary layer effects, but the stream will not remain locked on eitherside. This unit with a divider spacing of 2W is a boundary layer unittype a which if the spacing is less than 2W an amplifier of the firstclass, i.e., a proportional amplifier results. If the divider is spacedmore than three power nozzle widths, 3W, but less than eight powernozzle widths, 8W, from the power nozzle, then the power stream remainslocked onto one of the chamber walls and is a boundary layer type b.Complete blockage of the output passage of such a unit causes the powerstream to lock to a new flow pattern. A boundary layer unit having adivider which is spaced more than twelve power nozzle widths, 12W, fromthe power nozzle remains locked on to a chamber wall even though thereis complete blockage of the passage connected to the aperture towardwhich the power stream is directed, and thus it is a boundary layer unittype 0. Another factor effecting the type of operation achieved by theseunits is the pressure of the fluid applied to the power nozzle relativeto the width of the chamber. In the above examples, the types ofoperation described are achieved if the pressure of the fluid is lessthan 60 p.s.i.

If, however, the pressure exceeds p.s.i. the expansion of the fluidstream upon emerging from the main nozzle is sufficiently great to causethe stream to contact both side walls of the chamber and lock on isprevented. Lock-on can be achieved at the higher pressures by increasingthe widths of the chamber.

The present invention relates specifically to continuously variableamplifiers; that is, amplifiers of Class I. In systems of this type, theoutput signal is related by a proportionality factor to the input signaland it is desirable to eliminate boundary layer effects at least to theextent that they tend to produce operation as a Class IIB or Class IICamplifier. As previously indicated, boundary layer effects may becompletely eliminated or reduced to an acceptable value by maintainingthe proper pressure in the interaction fluid chamber, by setting backthe side walls a great distance from the power stream, by having theside walls diverge outwardly from the nozzle, or by a combination ofthese. In any case, the controlling criterion for design of an amplifierunit as a proportional amplifier is to insure that under no operatingcircumstances will an appreciable fraction of a side wall be disposed inclose proximity to a high velocity portion of the streams.

It is, accordingly, an object of the present invention to provide afluid amplifier having no moving parts which is capable of producing anoutput fluid signal having a pressure, power, or mass flow variationrelated to deflection of the stream which is greater than the pressure,power or mass flow variation required to produce the deflection.

It is another object of the present invention to provide a fluidamplifier having no moving parts in which amplification depends upon themagnitude of deflection of a stream of fluid resulting from adifferential in control fluid flow applied transversely of the directionof flow of the fluid stream.

It is another object of the present invention to provide a fluidamplifier system employing no moving parts in which amplificationdepends upon the magnitude of deflection of a power stream resultingfrom a differential in control fluid flow applied transversely of thedirection of flow of the fluid stream and in which the fluid stream isconfined in a direction perpendicular or normal to the deflection planeof the fluid stream.

It is yet another object of the present invention to provide a fluidamplifier employing no moving parts in which amplification depends uponthe magnitude of deflection of a stream of fluid resulting from adifferential in control fluid flow applied transversely of the directionof flow of the fluid stream and in which the fluid stream is initiallycaused to divide substantially equally between two outlet passages.

It is still another object of the present invention to provide a fluidamplifier employing no moving parts, in which amplification depends uponthe magnitude of the deflection of a fluid stream initially positionedto divide equally between two outlet passages, which deflection resultsfrom a differential in control fluid flow applied transversely of thedirection of flow of the fluid stream and in which the fluid stream isconfined by walls or by other fluid in a direction perpendicular to theplane of the deflection of the stream.

A further object of the invention resides in the provision of a fluidamplifier having no end wall losses, by virtue of utilization oftoroidal or cylindrical geometry in stream forming, controlling andcollecting components of the amplifier.

It is another object of the present invention to provide a novelacoustic amplifier having no moving parts.

It is a further object of the invention to provide a speed controldevice for a moving vehicle employing a fluid amplifier having no movingparts as a control element.

It is still another object of the present invention to provide a systemfor correcting the attitude of an aircraft in 9. response to attitudesensors, by means of a pure fluid servo system.

Still another object of the present invention resides in the provisionof a pure fluid servo having no moving parts.

The above and still further objects, features and advantages of thepresent invention will become apparent upon consideration of thefollowing detailed description of one specific embodiment thereof,especially when taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a plan View of a fluid-operated system in accordance with theprinciples of this invention.

FIG. 1a is an end view of the system shown in FIG. 1 With means forapplying fluid to the system.

FIG. lb is a cross section of FIG, 1 taken along the line 1b1b.

FIG. 2 is a plan view of another embodiment of the system shown in FIG.1.

FIG 2a is an end view of the embodiment of FIG. 2 with means forapplying fluid to the system.

FIGS. 3 and 3a show a stacking arrangement for a pair of fluid-operatedsystems shown in FIGS. 2 and 2a.

FIG. 4 schematically illustrates an arrangement for utilizing the systemshown in FIGS. 1 and 1a.

FIG. 5 shows another arrangement for utilizing the system shown in FIGS.1 and 1a.

FIG. 6 schematically illustrates another arrangement for utilizing thesystem shown in FIGS. 2 and 2a.

FIG. 7 is a plan view of a fluid amplifier system specifically designedto provide pressure amplification.

FIG. 8 is a plan view of a fluid amplifier system specifically designedto provide flow amplification.

FIG. 9 is a plan view of a fluid amplifier system specifically designedto provide for power amplification.

FIG. 10 is a plan view of a toroidal fluid amplifier system employingthe principles of the present invention.

FIG. 11 is a cross sectional view taken along section line 11 of FIG.10.

The fluid-operated system 10 of this invention consists basically of apower nozzle through which a fluid, for example, compressed air from asuitable source, passes; a control nozzle through which fluid underpressure can flow and impinge upon the fluid issuing from the powernozzle; and two or more apertures for receiving the fluid from the powernozzle. The apertures, power nozzle and control nozzle are positionedsuch that when the fluid from the control nozzle impinges upon the fluidissuing from the power nozzle, the apertures will receive varyingamounts or proportions of fluid depending upon the quantity and velocityof the fluid issuing from the control nozzle. and the functioning ofthese means is based upon variations in proportions of fluid flow intothe apertures.

FIGS. 1 and 1a illustrate one embodiment of the fluidoperated system ofthis invention. The fluid-operated system referred to by numeral 10 isformed by three fiat plates 11, 12 and 13 respectively. Plate 13 ispositioned between plates 11 and 12 and is tightly sealed between thesetwo plates by machine screws 14. Plates 11, 12 and 13 may be composed ofany metallic, plastic, ceramic or other suitable material. For purposesof illustration, plates 11, 12 and 13 are shown composed of a clearplastic material.

The substantially Y-shaped configuration cut from plate 13 provides afluid supply nozzle 15, a control nozzle 16, and apertures 17 and 18Nozzle 15 and nozzle 16 are adjacent to each other and are atsubstantially right angles. Nozzles 15 and 16 form constricted throats15a and 16a, respectively. The input ends 15b and 16b of nozzles 15 and16 communicate with bores and 21, respectively, formed in plate 12. Theoutput ends 17b and 18b of apertures 17 and 18, respectively,communicate with bores 22 and 23, respectively, in plate 12. Orifices17a and 18a form openings for apertures 17 and 18, respectively, and aresymmetrically spaced relative to nozzle 15. Both Suitable means areconnected to the apertures 1G orifices 17a and 18a have identicalcross-sectional areas in this embodiment.

Bores 20, 21, 22 and 23 are internally threaded so that tubes 25, 26, 27and 28 which are externally threaded can be tightly held in theirrespective bores. The end of tube 25 extending from plate 12 is attachedto a source of fluid under pressure. This source is designated bynumerial 31. The fluid under pressure can be air or other gas, or wateror other liquid. Gas with or without solid or liquid particles has beenfound to work very satisfactorily in system 10, also the liquid may havesolid particles or gas bubbles therein. A fluid-regulating valve 62 mayalso be used in conjunction with source 31 to insure continuous flow offluid at a constant pressure. Such fluid-regulating valves are, ofcourse, conventional.

Since the fluid stream flowing from nozzle 15 is reduced incross-sectional area by the nozzle throat 15a, the velocity of the fluidincreases. Relatively small fluid pressures applied to nozzle 16 causesa jet to form which impinges at right angles to the jet exiting fromnozzle 15. This impingement will cause considerable displacement of thejet stream from the latter nozzle as it passes nozzle throat 16a and theprinciple can be termed momentum exchange, since the control jet fromnozzle 16 imparts momentum to the jet from nozzle 15. When nozzle 16does not apply fluid pressure against the jet issuing from nozzle 15,orifices 17a and 18a will receive equal proportions or quantities offluid. Thus the proportions of fluid flow from tubes 27 and 28 will beequal and constant. A relatively small fluid pressure applied to thestream issuing from nozzle 15 by the jet from nozzle 16 will causeaperture 18 to receive a much larger proportion or quantity of fluid.This is because the jet from nozzle 15 can be substantially deviated asit passes nozzle throat 16a. This momentum exchange principle isutilized by the present invention so that system 10 is capable ofperforming the functions of multiplication and amplification. It can beseen that small variations in fluid pressure applied to nozzle 16 causelarge variations in fluid pressure in tubes 27 and 28. Thus the system10 is capable of amplifying small pressure variations in tube 26.

One illustration of how the system 10 can be used to regulate the airspeed of a plane is illustrated in FIG. 4. Airplane 34 has the usualgasoline engine 35 for driving propeller 38. Engine 35 has a carburetor37 attached which feeds air and gasoline into the engine. Pilot tube 36is connected to nozzle 16 while nozzle 15 is connected to an airscoop39. Tube 27 is connected to the carburetor 37 while tube 28 exhauststhrough the trailing edge of win g 40. While only one system 10 andassociated tubes are shown in airplane 34, it will be evident that thenumber of systems used will depend upon the number of carburetors 37.

When the airspeed of airplane 34 increases, pitot tube 36 senses anincrease in air pressure which causes the jet from nozzle 16 to deflectthe air forced into nozzle 15 by airscoop 39 so that a larger proportionof air is deflected into tube 28. Less air will thus be fed intocarburetor 37 automatically reducing the speed of airplane 34. Adecrease in air speed of airplane 34 will cause less deflection of theair stream from nozzle 15 so that more air is fed into carburetor 37,thereby increasing the speed of engine 35 and airplane 34. The effect isthus to maintain essentially constant air speed.

Another illustration of a system which will utilize the amplifyingfeature of system 10 is shown in FIG. 5. In this figure exponentiallycurved horn 29 is attached to tube 26. Source 31 provides a constant,continuous source of air to nozzle 15. Anyone speaking into the enlargedend of this horn will cause pressure pulsations to occur in tube 26.These pulsations will be amplified by system 10. The amplifiedpulsations pass through tube-s 27 and 28 and into horns 37 and 38respectively. Amplified voice issues from horns 37 and 38.

FIGS. 2 and 2a illustrate a modification of the fluidoperated systemshown by FIGS. 1 and 1a. This modification is designated by numeral 100.In system a a second control nozzle 46 is positioned opposite thecontrol nozzle 16. Throats 16a and 46a are substantially of the samesize and shape. Input end 4612 of nozzle 46 communicates with tube 47threadedly fixed in bore 48. Nu meral 50, like numberal 33, representsany means which would cause a fluctuating fluid pressure.Fluid-regulating valve 62 insures that the system 10a receives constantquantities of fluid.

Since throats 16a and 4611 are in opposed relationship, variation influid pressure in either nozzle will cause amplified movement of the jetissuing from nozzle in accord with the momentum exchange principle. Ifboth nozzles 16 and 46 simultaneously receive fluid pressure, theresultant movement of the jet from nozzle 15 will depend upon thedifference between the magnitude of the two opposing fluid streams fromnozzles 16 and 46. Also, should one control nozzle be under a vacuum,the resultant effect upon the jet from power nozzle 15 will be thedifference between the two pressures. Thus, it can be seen that theresultant fluid pressure difference causes movement of the stream fromnozzle 15.

The above-described feature which amplifies the difference of twopressures from any two sources is utilized as shown in FIG. 6 as'a yawcontrol for a jet airplane. FIG. 6 shows jet airplane 54 which isbeginning to yaw or sideslip in the direction of arrow S so that theoncoming air approaches the airplane in the direction of arrow W. Tubes26 and 47 extend from parts 55 and 56 respectively, adjacent the nose ofthe plane, as shown. Movement of plane 54 through the air produces airpressure in tubes 26 and 47. Tube communicates with jet chamber 57 sothat nozzle 15 will issue a continuous stream of gas under pressure.Wind pressure acting in the direction of arrow W will cause an increasein air pressure in tube 26 with the result that the pressure in tube 26is greater than the pressure in tube 47. Nozzle 16 will thereupon issuea jet at higher pressure than that jet issuing from nozzle 46. As aresult, the fluid from nozzle 15 will be moved a larger proportionalamount into aperture 18. The greater air pressure issuing from tube 27will cause a greater reactive force than that produced by tube 28causing jet airplane 54 to turn about its center of gravity in thedirection of arrow R thereby aligning airplane 54 so that it headsdirectly into the wind.

FIGS. 3 and 3a illustrate another embodiment of the present invention.In these figures, two identical fluidoperated systems 100 shown in FIGS.2 and 2a are stacked on top of one another so that differential airpressures in tubes 27 and 28 can be amplified again.

This can be easily effected by merely connecting tubes 27 and 28 bymeans of suitable sleeves 61 to control nozzles 16 and 46. Source 31' isidentical to source 31 so that the power nozzle 15' can receivecontinuous air pressure. Air introduced into nozzles 16 and 46' will beamplified again and will issue from tubes 27 and 28' respectively. Theamplified variations in air pressure in tubes 27 and 28' can be utilizedto move expansible bellows, diaphragms, pistons or other fluidresponsive mechanisms, as will be evident to those skilled in the art.If so desired, further amplification can be eflected by addingadditional systems 10a to the stacking arrangement shown in FIG. 3. Insummary, this invention provides a fluidoperated system which has nomoving parts and which performs functions hitherto performed byelectronic or complex mechanical devices. The fluid stream issuing frompower nozzle 15 and the impinging streams from the control nozzles andapertures 17 and 18 perform in a manner similarly to a stream ofelectrons.

The specific amplifiers illustrated in FIGURES 1, 2 and 3 are allproportional amplifiers of the class I type as defined hereinabove. InFIGURE 1 the apex of the divider separating channels 17 and 18 islocated a distance from the outlet of the power nozzle 15a equal toapproximately 2 /2 times the width of the power nozzle. When the divideris so placed, and with the angle of divergance of the side walls of theunit about as illustrated in FIG- URE 1, lock-on is inhibited. In thisunit, the power stream is restricted in the N direction; that is, in thedirection normal to the plane of FIGURE 1.

The gain of the device of FIGURE 1 is not great since, as indicatedhereinabove, the angle through which the stream must be deflected toproduce a substantial change in the energy delivered to an outputpassage, such as 17 or 18, is large and therefore the power of thecontrol stream issuing from nozzle 16 must be relatively large. However,gain is achieved by this unit due to the fact that the integrity of thestream is retained as the power stream passes through the chamber, sothat the power stream can deliver greater power to the output channelthan is required to deflect the power stream.

Referring now specifically to FIGURE 2 of the accompanying drawings,there is provided a unit which operates as a proportional amplifier,like FIGURE 1, but has a greater gain. Specifically, in the unit ofFIGURE 2, the divider is displaced approximately four widths of thepower nozzle from the end of the power nozzle, whereas in FIGURE 1 thedisplacement is 2 /2 widths. Consequently, the angle of deflection ofthe power stream required to produce a predetermined variation in anoutput parameter at one of the output passages 17 and 18, in FIGURE 2 isless than the angle required to produce a corresponding change in theoutput passages in the unit of FIGURE 1. The required input controlpower is thus reduced. In FIGURE 2, as in FIGURE 1, the apparatus hassome boundary layer effects, but these effects are not dominant becauseof the large angle of divergence of the side walls relative to the axisof the power nozzle. Lockon may also be prevented by a combination of alarge setback of the side Walls and an appropriate angle of divergenceof the side walls.

In both of the units of FIGURES 1 and 2, the stream initially dividesequally between output passages 17 and 18 and therefore a push-pulloutput signal is derived across the output passages and apush-pull-actuated loa-d device may be connected across tubes 27 and 28.As indicated hereinabove, this type of arrangement improves efiiciencyand, under some conditions, increases power gain in that the deflectionof the power stream adds to the power delivered to one end of the loaddevice while subtracting an equal amount of power from the other end ofthe load device. Therefore a two-fold or push-pull effect is achieved.

The apparatus of FIGURE 3 illustrates the cascaded amplifier employingsubstantially two amplifiers of the type illustrated in FIGURE 2, and itis intended to emphasize the fact that these units may be cascaded andconnected serially, and that the load device mentioned may be anotherfluid amplifier.

The efificiency and gain of the units of FIGURES 1 through 3 is, undersome flow and load conditions, maximized by having the stream divideequally, in the absence of a control signal, between the outputpassages. It is not intended to limit the structure of the invention tosuch an arrangement, and it is possible by employing a lock-on techniqueto cause an unbalanced initial flow. This unbalance can be provided bypositioning the flow divider asymmetrically, by bleeding a small amountof fluid into one of the control nozzles from the power nozzle, or bysupplying to one of the control nozzles fluid under pressure from anexternal source of fluid under pressure. This unbalance may also beprovided by employing the boundary-layer lock-on principles described byR. E. Bowles and R. W. Warren in their copending application referred tohereinabove. The placement of the divider is optional, and it may belocated so as to provide any desired initial proportioning of the fluidbetween the apertures, or passages.

Each of the various types of load device requires a 13 different type offluid amplifier, as previously indicated. Specifically, a pressure loadrequires that each output passage be relatively small compared to thewidth of the power stream; a mass flow load requires that each outputpassage be approximately as large as the power stream; and a poweramplifier requires that each output passage be intermediate in sizebetween these, say A to the width of the power stream. For maximumefliciency and output power the output passages should be approximatelythe same width as the high velocity center portion of the power stream.For maximum power gain the output passages should be considerablynarrower than the high velocity center portion of the power stream. Agood compromise which gives a good power gain and good eificiency can bemade by making the output passages approximately half the width of thehigh velocity portion of the power stream.

Referring now to FIGURE 7 of the accompanying drawings there isillustrated an embodiment of a fluid amplifying system 65 specificallydesigned to provide a pressure gain, that is to utilize a low inputpressure or low input pressure difference to control a higher outputpressure or pressure difference. Fluid under pressure is suppliedthrough bore 66 to power nozzle 67 which issues a stream of fluid intointeraction region 68. Control nozzles 69 and 71 are arranged in amanner similar to that shown in FIGURE 2 to deflect the power stream offluid issuing from nozzle 67. When a greater quantity of fluid flowsfrom control nozzle 71 than flows from control nozzle 69, the powerstream will be deflected to the right as seen in FIGURE 7. When agreater quantity of fluid flows from control nozzle 69 than flows fromcontrol nozzle 71, then the power stream will be deflected to the left.Passages 72 and 73 of FIGURE 7 have narrow orifices 74 and 76,respectively, so positioned that the center of the undeflected powerstream from power nozzle 67 passes freely between these orifices throughpassage 77 into the ambient pressure region surrounding amplifier 65.Orifices 74 and 76 each *have a width which is one tenth the width W ofthe constricted throat 78 or nozzle 67, and are located at a distance of6W from constricted throat 78. Orifices 74 and 76 are positionedsymmetrically with respect to the center line of nozzle 67, preferablywhere the maximum rate of change of pressure with lateral displacementoccurs. With this arrangement, orifices 74 and 76 respond to the totalpressure, dynamic plus static, of the fluid in the side of the powerstream. When the power stream is undeflected, that portion having thegreatest total pressure flows freely through passage 77. Because ofentrainment by the power stream of fluid in the interaction region 68,and because of spreading of the fluid in the power stream by expansion,there is a rapid variation of total pressure within the power streamwith lateral distance from the center line of the power stream. At adistance equal to one nozzle width W from that centerline, the totalpressure is greatly reduced, perhaps to -25 percent of its value at thecenterline. Thus, considering the rate of change of total pressureproceeding from the centerline of the power stream laterally outward,there is a point at which a small lateral change in position of theorifices 74 and 76 would cause a large change in the pressure developedin passages 72 and 73. In a similar manner, a small change in thedirection of flow of the power stream from nozzle 67 can also causelarge changes in the total pressure of the fluid in passages 72 and 73.The differential fluid flow from nozzles 71 and 69 controls thedirection of flow of the power stream from nozzle 67. Thus when themomentum of the fluid issuing from nozzle 71 is greater than themomentum of the fluid flowing from nozzle 69, the power stream will bedeflected to the right, causing the pressure developed in passage 72 tobe increased and the pressure in passage 73 to be decreased from thepressures occurring in these passages when the power stream isundeflected.

A satisfactory width of passage 77 in this embodiment is 2W/3. Theinfluence of side walls and boundary layer effects are avoided in thepressure amplifier system of FIGURE 7 by providing that the power streamand control streams interact in a region open on both sides to theambient pressure, by providing wide passages 79 and 81.

The pressures developed in passages 72 and 73 of FIGURE 7 aretransmitted through bores 82 and 83, respectively, and through tubes 84and 86, respectively, to chambers 87 and 88, respectively, ofdiaphragmactuated switch 89. When the pressure in chamber 87 exceeds thepressure in chamber 88 by an amount suflicient to compress spring 91,the center portion of flexible diaphragm 92 moves to the left and causeselectrical contact 93 to move away from electrical contact 94, and thusinterrupts the electrical circuit comprising wires 96 and 97, insulatingblocks 98 and 99, threaded screw 101, and threaded insulating block 102.By turning screw 101 it is possible to adjust the diaphragm-actuatedvalve so that the electrical circuit will be interrupted at anypredetermined value of pressure differential in chambers 87 and 88. Theoverall operation of pressure amplifier system 66 is that it provides ameans for a very small pressure or pressure difference applied throughbores 103 and 104 to nozzles 71 and 69, respectively, to control thedelivery of electrical power from a suitable electrical power source toan electrical load.

Walls 106 and 107 surrounding passages 72 and 74 respectively are shortand have a small width in order to prevent back pressure developed inthese passages from distorting the flow pattern of the main powerstream.

In FIGURE 8 is shown an fluid amplifying system specifically designed toprovide a flow amplification, that is to utilize a small rate of volumeflow or mass flow rate to control a larger output volume or mass flowrate. Since a high rate of output flow is desired, apertures 116, 117,and 118 separated by dividers 119 and 121 each have a width equal totwice the width of the throat of the power nozzle, that is 2W, where Wis the width of the power nozzle. This permits substantially all of thefluid flowing from nozzle 122 to be recovered, along with the fluidentrained by the power stream because of viscous drag, turbulence, orother interaction between the power stream and other fluid in theinteraction region 123. This will include fluid from the controlnozzles. Dividers 124 and 126 divert fluid not flowing into one of theapertures 116, 117, or 118 into the ambient pressure region surroundingfluid amplifier system 115 through wide passages 127 and 128.

Wide passages 127 and 128 insure that the pressure on both sides of thepower stream is substantially ambient pressure. Since neither pressurenor power need be conserved in a fluid flow amplifier, apertures 116,117 and 118 are satisfactorily located at a distance of ten to twentynozzle widths from the power nozzle. The flow amplifier shown in FIGURE8 employs a distance of 14W between the throat of the power nozzle andthe receiving apertures. A large spacing such as this permits the powerstream to entrain substantial quantities of fluid in the in teractionregion 123, and this effect increases the mass or volume rate flow intothe apertures above the rate which would have occurred withoutentrainment, thus providing additional gain because of this entrainment.The apertures 116, 117, and 118 communicate, respectively, with suitableoutput passages 129, 131, and 132. T he latter in turn communicate withtubes 133, 134, and 136, respectively, and these supply fluid towhistles 137, 138, and 139, respectively. The whistles 137, 138, and 139may be selectively energized by providing suitable controlling flowrates to control nozzles 141 and 142,

In FIGURE 9 is shown a fluid amplifying system specifically dseigned toprovide a power output to a load device. Fluid under pressure issupplied through bore 151 to power nozzle 152 which issues a powerstream of fluid. The power stream passes through region 153 and impingeson apertures 154- and 156 formed by the leading edges of walls 157 and158. Apertures 154 and 156 each have a width of W/2, that is half thewidth of the throat of the power nozzle. These apertures are placed at adistance of SW from the power nozzle and are separated by a passage 159having a width X. When the power stream flows at subsonic rates, X maybe reduced to zero, but when a supersonic power stream is used, aspacing of one-half power nozzle width, that is X =W/2 provides a meansfor preventing the back pressure in passages 161 and 162 from distortingthe flow pattern of the power stream. Passages 161 and 162 communicatewith bores 163 and 164 respectively, and with tubes 166 and 167respectively, which supply fluid to ends 168 and 169 of cylinder 171 sothat the piston 172 will move in response to the differential pressuredeveloped in passages 161 and 162.

The output power of a fluid amplifier employing an incompressible fluidcan be calculated by obtaining the product of pressure times volume flowrate. In the case of a compressible fluid driving a thermodynamic load,the output power of interest is the kinetic energy per second due to thetranslational velocity of the fluid plus the thermodynamic enthalpy flowrate per second.

The overall operation of fluid amplifying system 150 shown in FIGURE 9is as follows: When the input fluid pressure or flow rate suppliedthrough bore 173 to nozzle 174 exceeds the fluid pressure or flow ratesupplied through bore 176 to nozzle 177, then the fluid issuing fromnozzle 174 will exert a greater influence than the fluid issuing fromnozzle 177, and the power stream from nOZZle 152 will be deflected tothe right thus increasing the pressure in passage 161, tube 166 andcylinder end 168 above the pressure in passage 162, tube 167, andcylinder end 169, and the piston 172 will move to the left.

In the fluid amplifying units illustrated in FIGURES l, 2, 3, 7, and 9,a planar construction is employed in which the fluid is constrained bythe top and bottom plates, shown as plates 11 and 12 of FIGURES 1, and2. The purpose of these plates is to prevent spreading of the powerstream and control streams in a direction normal to the deflectionplane, i.e., to prevent spreading in the N direction. While it isadvantageous to prevent spreading of the streams in the N direction, theuse of these plates introduces top and bottom plate losses because ofthe friction of the fluid passing near these plates. The fluid incontact with the top and bottom plates is substantially at rest while atsome distance from the plates the fluid is flowing more rapidly. In theintervening region the fluid is undergoing a shearing action withviscous or turbulent losses. The central part of the stream, midwaybetween the top and bottom plates, undergoes much smaller lossesattributable to this shearing action, since, in this central region,each small portion of each stream is adjacent to other portions of thatsame stream flowing at almost the same velocity. It is thus seen that byhaving a large percentage of the streams remote from the top and bottomplates, the relative effect of these losses can be made small. This canbe done by making plate 13 of FIGURE 1a thicker. Thus the amplifier isextended in depth. A different method of increasing depth of a fluidamplifier is to cause the pattern of FIGURE 2 to be rotated about anaxis passing along the bottom edge of FIGURE 2. The resulting fluidamplifier will be substantially symmetrical about the axis of rotation.It will thus be a toroidal fluid amplifier. By rotating the patterncompletely around in a circle the figure closes on itself, hence no topand bottom plates are required, and there are no top and bottom platelosses.

FIGURE 10 is a plan view of a toroidal two stage fluid amplifier 191.FIGURE 11 is a cross sectional view of the amplifier 191 taken along theline 1111 of FIG- URE 10. Referring now to both FIGURES 10 and 11, fluidis supplied through tube 192 to toroidal nozzle 193.

Nozzle 193 issues a jet of fluid which flows radially outward in a planeperpendicular to the axis of revolution XX of amplifier 191. Nozzle 193is aligned with the aerodynamically-rounded divider 194 so thatinitially substantially equal fluid flow rates occur in toroidalpassages 196 and 197. Divider 194 and passages 196 and 197 extendcircumferentially completely around axis XX, being everywhere alignedwith nozzle 193. Passage 196 is interrupted by twelve aerodynamicallystreamlined tubes 198, circumferentially and equally spaced, which arerequired for supplying fluid under pressure to toroidal nozzle 199.Tubes 198 are sealed to and provide mechanical support for toroidalnozzle 199. The input fluid signal for amplifier 191 is supplied throughinput tubes 201 and 202 which then pass the signal through manifolds 203and 204 respectively to control nozzles 206 and 207, respectively. Thedifferential fluid pressure or flow rate supplied to tubes 201 and 202causes a differential fluid flow rate out of nozzles 206 and 207 withthe result that the power stream from power nozzle 193 will be deflectedfrom its radially-outward flow pattern into a generally conical flowpattern. Control nozzles 206 and 207 provide substantiallycylindrically-shaped and oppositely-directed fluid flow patterns. If thepressure or flow rate supplied to tube 202 exceeds the pressure or flowrate supplied to tube 201, then the pressure and flow rate in passage196 will be increased, while the pressure and flow rate in passage 197will be decreased. Passages 196 and 197 supply toroidal control nozzles208 and 209 respectively, which issue substantially cylindrical,oppositelydirected control streams. The interaction between thesecontrol streams and the power stream flowing radially outward fromtoroidal nozzle 199 provides a second stage of fluid amplification.Toroidal output passages 210 and 211 are aligned with the center line ofpower nozzle 199 so that in the absence of an input signal to amplifier191, substantially equal pressures or flow rates occur in passages 210and 211. The differential flow rate of fluid issuing from controlnozzles will, however, cause a deflection of the power stream fromnozzle 199, resulting in an increased pressure or an increased flow ratein one of the output passages 210 or 211, and a decrease in pressure orflow rate in the other. Toroidal chambers 217 and 218 andcircumferentially-distributed equally-spaced bores 219 and 221 provide ameans for the ambient pressure of the fluid surrounding toroidalamplifier 191 to be communicated to both sides of the power streamissuing from nozzle 199, and thus insure that side wall influences andboundary layer effects are negligible. Disks 224 and 226 of amplifier191 are sealed together at surface 227.

As an example of the operation of toroidal amplifier 191 shown inFIGURES 10 and 11, if the input fluid signal supplied to tube 202 islarger than the fluid input signal supplied to tube 201, then there willbe greater fluid flow or greater pressure developed in passages 196 and211, manifold 212 and output tube 213, whereas there will be a lesserfluid flow or lesser pressure in passages 197 and 210, manifold 214 andoutput tube 216. The pressure P+ of the fluid supplied to nozzle 193through tube 192 is selected upon the type of signal being amplified. Ifthe input signal is very small, and if high speed of response and highoutput power are not required of the first stage of the amplifier, thenin order to keep the noise level low, a low value of P+ pressure can beused. When air is used as the fluid, a pressure of 5 pounds per squareinch will give a satisfactorily low noise level. If greater speed ofresponse and higher output power are desired, and if a low noise levelneed not be maintained, then a pressure of 60 pounds per square inch orhigher may be used. For many applications it is desirable to supply thefirst amplification stage with a low pressure through tube 192, and thesecond stage with a higher pressure through tube 223, thus achieving lownoise in the first stage where the signal is small, and higher speed of'17 response and greater output power in the second stage where thesignal is larger.

It can easily be seen that by a suitable modification, the power nozzlesof amplifier 191 of FIGURES and 11 can be arranged to provide asubstantially cylindrical power stream flowing generally coaxially withaxis XX, and that the control nozzles can be arranged to issue controlstreams flowing radially outward and radially inward and thus deflectingthe cylindrical power stream radially outward or radially inward,without departing from the basic principle of a toroidal geometry. Inother words, rotation of the fluid amplifier of FIGURE 2 about any axislying in the plane of that figure provides a toroidal amplifier havingno top and bottom plate losses, since this rotation produces athree-dimensional configuration which closes on itself.

The toroidal amplifier of FIGURES 10 and 11 provides, in addition to itsfreedom from top and bottom plate losses, a compact fluid amplifier witha high powerhandling capability, and, because of the circular symmetry,it provides a means of achieving maximum speed of response. Since thepath length of input and output signals is substantially the same forall parts of the amplifier. This equality of input signal path lengthsis provided by input manifolds 203 and 204 which supply the fluid inputsignal from a point on the axis of revolution XX. Similarly, outputmanifolds 212 and 214 bring the fluid output signal to a point on theaxis of revolution, since all points on a circle are equidistant from apoint on its axis, the path lengths and time delays through each portionof the toroidal amplifier are substantially equal, and the strength ofthe signals to and from each portion of the toroidal amplifier will besubstantially equal.

While I have employed, in the various arrangements shown in theaccompanying drawings, power nozzles and control nozzles oriented atsubstantially right angles to each other in order to illustrate a meansof achieving a high gain, it is clear that other angles than rightangles may be used. When an angle other than a right angle is usedbetween the power stream and its control stream, the deflection of thepower stream will be determined by the component of the control streammomentum which is at a right angle to the power stream, i.e., by thecomponent of the force of the control stream which is directedtransversely of the power stream.

While I have described and illustrated several specific embodiments ofmy invention, it will be clear that variations of the details ofconstruction which are specifically illustrated and described may beresorted to without departing from the true spirit and scope of theinvention as defined in the appended claims.

I claim:

1. A fluid operated acoustic device, comprising at least one horn, apure fluid amplifier of the beam deflection type having at least oneoutput channel communicating with said at least one horn, a source of aband of acoustic frequencies, said fluid amplifier having an inputchannel communicating with said source.

2. A fluid-operated acoustic device comprising at least one acoustichorn; a fluid amplifier including means for issusing a stream of fluid,plural passages located downstream of said stream of fluid inintercepting relationship thereto, and means for developing a variablepressure gradient having a component directed transversely of saidstream of fluid to vary the proportions thereof intercepted by saidpassages; said fluid amplifier having at least one of said passagesconnected to said horn, said fluid amplifier having an input channel andmeans for coupling said input channel to a source of acoustic energy.

3. A fluid ope-rated acoustic amplifier comprising at least one acousticborn, a fluid amplifier including a power nozzle and a control nozzleangularly disposed with respect to each other for issuing fluid streamsin interacting relationship, said fluid amplifier additionally includingat least one output passage located downstream of the control and powernozzles for receiving fluid therefrom and supplying said fluid to atleast one acoustic horn, and a source of a band of acoustic frequencies,said control nozzle connected to receive the acoustic frequencies fromsaid source.

4. The acoustic amplifier as claimed in claim 3 wherein the shape ofsaid acoustic horn is substantially that of an exponential function.

5. A fluid operated acoustic amplifier comprising a pure fluid amplifierof the beam deflection type wherein all elements forming said amplifierremain stationary during operation thereof, means for supplying a powersignal to said amplifier, means for receiving and supplying an acousticsignal to said amplifier so that the acoustic signal varies thedisplacement of said power signal in said amplifier, and means forreceiving the amplified acoustic signal.

6. A pure fluid amplifier system of the type wherein all elementsforming said amplifier remain stationary during operation thereofcomprising a pure fluid amplifier including an interaction chamber forreceiving interacting fluid streams, power and control nozzles angularlydisposed with respect to each other for issuing interacting fluidstreams into said interaction chamber, the momentum of a smallerenergized fluid stream issuing from the control nozzle displacing alarger energized fluid stream issuing from the power nozzle in saidinteraction chamber, plural passages for receiving the displaced powerstream, and means connected to receive the fluid output from saidpassages for converting the output thereof into an acoustic output.

7. The fluid operated acoustic device comprising at least one acoustichorn, a fluid amplifier connected to said acoustic horn, said acoustichorn including an interaction chamber, means for issuing a constrictedstream into said interaction chamber, plural passages located downstreamof said chamber for receiving fluid therefrom, at least one of saidpassages connected to said horn, means responsive to acoustic energy fordeveloping a variable pressure gradient having a vector componentdirected transversely of said constricted stream of fluid in saidinteraction chamber so as to vary the quantity'of fluid intercepted byeach of said passages.

8. A fluid operated acoustic amplifier comprising a pure fluid amplifierhaving two fluid output passages, a power nozzle for issuing a mainstream of fluid toward said output passages, at least one control nozzlefor issuing a control stream of rfluid into intercepting relationshipwith said main stream so as to differentially vary the quantity of fluidflowing into said fluid output passages, an acoustic horn coupled to oneof said fluid output passages to receive fluid therefrom and means forapplying acoustic signals to said control nozzle.

9. An air operated acoustic amplifier comprising a pure fluid amplifierhaving two fluid output passages, a power nozzle for issuing a mainstream of air toward said output passages, at least one control nozzlefor issuing a control stream of air into intercepting relationship withsaid main stream so as to dilferentially vary the quality of air flowinginto said fluid out-put passages, an acoustic horn coupled to one ofsaid fluid output passages to receive air therefrom and means forapplying acoustic signals in air to said control nozzle.

10. The combination according to claim comprising a second acoustic horncoupled to the other of said outlet passages, said acoustic horns beingoppositely directed so as to radiate sonic energy in oppositedirections.

11. A fluid operated acoustic amplifier comprising a proportional purefluid .amplifier of the interacting stream type including a pair offluid outlet passages, a stream interaction region, a power nozzle forissuing a main stream of fluid through said stream interaction regiontoward said fluid outlet passages, a control nozzle for issuing acontrol stream of fluid into said interaction region in interceptingrelationship with said main stream so as to deflect said main stream asa function of said control stream and vary the proportion of fluiddirected to said outlet passages, means for applying acoustic signals tosaid control nozzle and an accoustic horn for receiving the variablefluid flow directed to one of said outlet passages.

12. A fluid operated acoustic amplifier comprising a pure fluidamplifier of the beam deflection type having a main input passage, acontrol flu-id input passage and two fluid output passages an acoustichorn connected to receive fluid directly from one of said outputpassages, and means for applying acoustic signals to said control fluidinput passage.

References Cited by the Examiner UNITED STATES PATENTS 782,146 2/ 1905Laudet 181.5 5 1,216,946 2/1917 Clement 340-8 2,824,292 2/ 1958Christoph 340-43 BENJAMIN A. BORCHELT, Primary Examiner.

KATHLEEN CLAFFY, Examiner.

10 J. W. MILLS, R. F. STAHL, Assistant Examiners.

1. A FLUID OPERATED ACOUSTIC DEVICE, COMPRISING AT LEAST ONE HORN, APURE FLUID AMPLIFIER OF THE BEAM DEFLECTION TYPE HAVING AT LEAST ONEOUTPUT CHANNEL COMMUNICATION WITH SAID AT LEAST ONE HORN, A SOURCE OF ABAND OF ACOUSTIC FREQUENCIES, SAID FIRST AMPLIFIER HAVING AN INPUTCHANNEL COMMUNICATING WITH SAID SOURCE.